Spring bias for damper door of an air conditioning unit

ABSTRACT

A device for biasing a damper door covering the port of a partition separating the evaporator and condensing sections of an air conditioning unit comprises an over-center leaf spring. The spring is an open-ended element connected at one end to the partition on one side of the axis about which the damper door pivots and at its other end to the door on the opposite side of the axis. The axis is within the confines of the line of force between the ends of the spring and the spring itself when the damper door is in its closed position so that the bias force is at its maximum value. As the door is pivoted about its axis towards the open position, the line of force moves towards the axis so that the bias decreases as the door opens.

United States Patent Murnane et al.

[ Nov. 25, 1975 1 1 SPRING BIAS FOR DAMPER DOOR OF AN AIR CONDITIONINGUNIT [73] Assignee: Carrier Corporation, Syracuse, NY.

[22] Filed: Oct. 25, 1974 [21] Appl. No.: 517,975

3,831,395 8/1974 Levy 62/427 Primary Examiner-William J. Wye Attorney,Agent, or FirmJ. Raymond Curtin; Barry E. Deutsch [57] ABSTRACT A devicefor biasing a damper door covering the port of a partition separatingthe evaporator and condensing sections of an air conditioning unitcomprises an over-center leaf spring. The spring is an open-endedelement connected at one end to the partition on one side of the axisabout which the damper door pivots and at its other end to the door onthe opposite side of the axis. The axis is within the confines of theline of force between the ends of the spring and the spring itself whenthe damper door is in its closed position so that the bias force is atits maximum value. As the door is pivoted about its axis towards theopen position, the line of force moves towards the axis so that the biasdecreases as the door opens.

4 Claims, 5 Drawing Figures US. Patent Nov. 25, 1975 Sheet10f2 3,921,416

1 SPRING BIAS FOR DAMPER DOOR OF AN AIR CONDITIONING UNIT BACKGROUND OFTHE INVENTION 1. Field of the Invention V v The present inventionrelates to air Conditioning units, and in particular to means forbiasing ventilation and exhaust dampers disposed over ports in thepartition separating a condenser and evaporator sections of such units.

2. Description of the Prior Art Air conditioning units such as room airconditioners generally include refrigeration circuits having anevaporator and a condenser. The unit is generally divided by a partitioninto an evaporator section and a condenser section. The unit is normallymounted with the evaporator section being adjacent the space beingcooled by the unit and in communication with the air in that space, andthe condenser section is in communication with outdoor air. Refrigerantflows through the refrigeration circuit and absorbs heat from the roomair flowing through the evaporator section causing the refrigeranttherein to evaporate and flow towards the condenser section. Refrigerantin the condenser section gives up absorbed heat to the outdoor airflowing over the condenser causing the refrigerant to condense. Inaddition to the capability of controlling the temperature of the air inthe space being conditioned, it is often desirable to remove stale airfrom the space or to admit fresh, outdoor air to the space. This isaccomplished in various air conditioning units by the provision ofappropriately positioned ports in the foregoing partition which can beselectively opened and closed to control the flow of air between theevaporator and condenser sections. Although it is common to provide aport for exhaust air and a second port for ventilation air, it isentirely possible to provide but one of the foregoing ports.

Ports of the aforementioned type are usually located to make use ofpressure differentials for forcing the air in the desired directionthrough the partition. Such pressure differentials are normally createdby means of appropriate fans and blower wheels disposed in therespective sections. The use of such ports is known in the art, asevidenced by US. Pat. No. 2,986,016 which issued on May 30, 1961, toGillham et al.

Damper doors are conventionally provided for selectively opening andclosing exhaust and vent port doors in room air conditioners. Aneffective construction of damper doors of the foregoing type and theassociated apparatus for selectively opening and closing the doors isdisclosed in US. Pat. No. 3,823,574 which issued on July 6, 1974 toTheodore 5. Bolton. The latter patent discloses a pair of pivotallymounted damper doors which are biased towards the closed positions bycompression springs connected at one end to the partition and at theother end to one of the doors. The doors are opened by means of a leverwhich selectively engages the doors and overcomes the bias of therespective springs.

SUMMARY OF THE INVENTION An object of the present invention is to biasthe damper doors of air conditioning units towards their closed positionin an approved manner.

A more specific object of the present invention is to provide a devicefor biasing a damper door of a room air conditionertowards its closedposition in a manner I which assures strong closing of the dooryet whichfacilitates the opening thereof.

Another object of the present invention is to provide an economicalspring for biasing a damper door towards its closed position whilefacilitating the opening of the door. 1

Another object of the present invention is to provide a spring of thepreceding type which can be modified to also bias the damper doortowards its open position after the door has been opened by apredetermined amount.

Another object of the present invention is to provide a spring of theforegoing type which is simple in construction, reliable in operation,and easy to fabricate and assemble.

Other objects will be apparent from the description to follow and fromthe appended claims.

The preceding objects are achieved'according to a preferred embodimentof the invention by the provision of an overcenter open-ended leafspring connected at one end to the partition separating the evaporatorand condenser sections of a room air conditioner on one side of the axisof pivotal movement of a damper door,'and at its other end to the damperdoor on the opposite side of the axis. When the damper door is in itsclosed position, the axis is within the confines of the line of forceextending between the ends of the spring and the spring, and the springbias is at its maximum amount. As force is exerted on the door to openthe door from its port closing position, the line of force moves towardsthe axis so that the force required to open the door decreases as thedoor is opened. The spring can be so constructed and assembled on thepartition and the door so that the line of force passes over the axiswhereby the spring then biases the door towards its open position.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a pictorial representationof a portion of the interior of a room air conditioner showing damperdoors over the vent and exhaust ports in a partition in the unit, andthe apparatus for operating the doors.

FIG. 2 is a pictorial representation of a spring according to theinvention for biasing the damper doors towards their closed positions.

FIGS. 3 and 4 are top partial views of the apparatus shown in FIG. 1with one of the damper doors in its open and closed positionsrespectively.

FIG. 5 is a schematic side view of a self-contained room airconditioning unit having dampers of the type described herein.

- DESCRIPTION OF THE PREFERRED EMBODIMENT The embodiment of theinvention described below is adapted for use in a self-contained roomair conditioning unit, although it is to be understood that theinvention defines applicability in other forms .of air conditioningunits. The air conditioning unit described below includes a wall orpartition separating the unit into a condenser or outdoor section whichcommunicates with the outdoor or external air, and an evaporator orindoor section which is in communication with the room being airconditioned. An exhaust port is defined in the partition wherein thepressure on the evaporator side of the partition is greater than that onthe condenser side of the partition. and a vent port is provided at asection of the partition where the pressure on the condenser side ishigher than that on the evaporator side. Thus. air can be exhausted fromthe room to the outdoors through the exhaust port by virtue of thepressure differential existing across that port. while fresh air can bevented into the room by virtue of the pressure differential existingacross the vent port. A pair of doors are pivotally mounted adjacenteach of the ports for opening and closing the ports. The doors arebiased to their closed positions by over center springs according to thepresent invention. A rotatable lever can be provided having an arm forexerting force on the doors to effect their opening.

Referring now to the drawings. FIG. shows in schematic form aself-contained room air conditioning unit having appropriately placedexhaust and vent ports. The unit includes a condenser section in whichare located a condenser 1 and a fan 3 for directing ambient air over thecondenser coils as indicated by the arrow, and an evaporator sectionincluding an evaporator 5 and a blower wheel or other fan 7 for drawingroom air over the evaporator coil and directing that air back into theroom as indicated by the arrow. The two sections of the unit areseparated and isolated by a partition or wall 9. The unit is adapted forinstallation in a room so that the evaporator section communicates withthe room air while the condenser section communicates with the outdoorair. The condenser and evaporator are part of a conventionalrefrigeration circuit which also includes a compressor and an expansiondevice (not shown). with the evaporator serving to absorb heat from roomair drawn over the evaporator coils by the blower which then returns thecooled air back into the room. The heat absorbed by the refrigerant inthe evaporator is thereafter transferred to the air being blown acrossthe condenser coils by fan 3. Partition 9 is located considerably closerto blower wheel 7 and to fan 3 so that the pressure P in the region ofblower wheel 7 is less than the pressure P on the condenser side ofpartition 9. Both of the pressures P and P, are suction pressures andare thus below the ambient pressure P The pressure P above blower wheel7 is higher than the ambient pressure and is also higher than thepressure P above fan 3 because of the relative characteristics of thetwo air moving devices. An exhaust port 13 is defined in wall 9 betweenthe region of pressure P and the region of pressure P so that when port13 is opened, air flows through the port into the condenser section.Similarly, a vent port 15 is defined in partition 9 between the regionof pressure P and the pressure P so that when port 15 is opened. airflows from the condenser section into the evaporator section andthereafter into the room.

The remaining figures illustrate apparatus for controlling the openingand closing of ports 13 and 15. The apparatus depicted enables thealternate opening of one of the ports and permits the closing of bothports; however, the apparatus is not adapted to open both portssimultaneously, since this would have the undesir able effect of simplycirculating air between the ports rather than transferring air to andfrom the room being air conditioned. An exhaust port door 17 has aportion 18 configured to cover and close exhaust port 13 and is mountedfor pivotal movement about an axis XX by a pair of tabs 19 extendingthrough wall 9 adjacent port 13. An open-ended, over-center leaf spring21 connected-at one end to door 17 on one side of axis XX and at itsother end to partition 9 on the other side of axis XX biases door 17 toits closed position. Spring 21 is shown in detail in FIG. 2, andincludes a generally arcuate portion 23 having a generally straight,opposing end portions 24 which are inclined slightly towards each other.Portions 24 terminate in small hooks or tabs 25 which are adapted toextend through corresponding openings in exhaust door 17 and in bentback portion 26 of partition 9. A portion 27 of wall 9 is configured toenable the air conditioning unit to accommodate a control box 29 whichcontains the operating buttons or the like for the unit. A second tab 31includes a first section 33 which is coplanar with portion 18, a secondsection 35 which is bent back transversely towards wall portion 27, anda third section 37 which is generally parallel to section 33. Thefunction of tab 31 will be apparent from the description to follow. Agasket 39 fabricated from some suitable material such as urethane foamis advantageously applied to door portion 18 engaging the wall surfacesurrounding exhaust port 13 when the door is moved to its exhaust portclosing position. The engagement of gasket 39 and the port edge enhancesthe degree to which the door seals the port against the passage of air.In order to prevent any materialswhieh could damage the air conditioningunit from passing through discharge port 13, a filter 41 can be affixedacross the port. Filter 41 may comprise a common filtering material suchas fine mesh screen.

Vent port 15 is disposed between condenser fan 3 and blower 7 to takeadvantage of the previously described pressure differential existing inthis area. A vent port door 43 is mounted for pivotal movement to openand close vent port 15. Vent door 43 includes a vent port closingportion 45 which is dimensioned to shut port 15 to the passage of air.Means are provided for biasing door 43 to its closed position, and it iscontemplated that a spring similar or identical to spring 21 beconnected to door 43 and partition 9 for this purpose in a mannersimilar to spring 21. However, for the sake of clarity, the provision ofsuch biasing means has been omitted with regard to door 45. For thepurposes of this description, it should be assumed that spring means areprovided for biasing door 45 about an axis parallel to axis XX towardsits vent port closing position. Again, it may be assumed, that theoperation of doors l7 and 43 can be coordinated so that the desiredsequence of door opening and closing events may be readily obtained. Agasket 55 fabricated from an appropriate material such as urethane foamis attached to door 43 for engaging the wall surface around vent port 15when door 43 is in its port closing position. A filter 57 which can bein the form of a fine mesh screen is advantageously provided across ventport 15 for preventing potentially damaging materials from passingthrough vent port 15 into the evaporator section of the air conditioningunit.

In order to effect the selective opening and closing of the two ports,an operating lever 61 is provided in the unit. Lever 61 is preferably aunitary piece which can be fabricated from molded plastic. and comprisesan actuating arm 63 engageable with tab 31, and a control arm 65 havinga manually engageable portion 67 for operating the lever. Arms 63 and 65extend transversely from a rotatable shaft 69 having a longitudinal axisof rotation Y-Y which is parallel to the axes of rotation of exhaustport door 17.

Actuating arm 63 includes at its end portion furthermost spaced fromshaft 69, cylindrical portions 51 and 71 which are engageable with tab31 of exhaust door 17. Control arm 65 is angularly displaced fromactuating arm 63 so that when the exhaust door is in its closedposition, manually engageable portion 67 is centrally disposed in a slot73 in the exterior of control box 29. In other words, the foregoingelements are arranged so that when the door is shut, control arm, 65 ismovable left or right as shown in FIGS. 4 and 5.

When exhaust port door 17 is closed, cylindrical portions 51 and 71 ofactuating arm 63 are in engagement with parallel section 33 of the tabas indicated in FIG. 2. When control arm 65 is moved counterclockwise orto the right as indicated in the drawings, a force is exertedtransversely on section 33 of tab 31 of the exhaust door, with theresulting torque causing door 17 to pivot about axis XX to open exhaustport 13. When control arm 65 has been so moved to a predeterminedextent, cylindrical portions 51 and 71 slide over section 35 ontosection 37 as shown in FIG. 4. When this occurs, the apparatus remainsin the condition shown in the drawing even after manual pressure isreleased from control arm 65. This occurs because the line of force FFextending between the ends of end portions 24 of spring 21 passes acrossthe axis XX of door 17 as the door is pivoted from its closed positionas shown in FIG. 3 to its open position as shown in FIG. 4. It can beseen from these drawings that spring 21 biases door 17 to its closedposition until such time as the line of force FF of the spring crossesthe axis XX. In addition, the maximum closing force exerted by spring 21is exerted when the door is closed, and this force diminishes as thedoor is pivoted towards its open position. When arm 65 is movedclockwise, portions 51 and 71 slide over section 35 onto section 33 andthereby exert a force on the tab to return the door to its port closedposition.

As noted before, control arm 65 may be suitably designed to operate door43 as well as door 17. Thus, clockwise movement of arm 65 will provide aforce to open door 43 as well as close door 17. Similarly,counterclockwise movement of arm 65 will cause door 43 to close as wellas door 17 to open. To further simplify construction of the airconditioning unit, a spring similar to spring 21 and a tab similar totab 25 may be incorporated in conjunction with door 43.

Spring 21 is of an extremely simple construction, comprising a unitarymember of an appropriate material such as spring stock. The part can bestamped on conventional equipment and should have a negligible cost.Installation of the part is extremely easy, merely requiring theinsertion of tabs 25 into appropriate openings in the door and partitionin which it is to be attached. The part is advantageously designed to besymmetrical so that it makes no difference which end is attached to therespective openings of the air conditioning unit. Furthermore, it isalso advantageous to use the same spring designed for both the exhaustand vent port doors, whereby the cost of the individual springs isreduced and the likelihood of confusion is eliminated.

The invention has been described in detail with particular reference toa preferred embodiment thereof. but it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention.

We claim:

1. In an air conditioning unit having a casing, a partition dividing theunit into an evaporator section and a condenser section, and a portextending through said partition for enabling the flow of air betweenthe evap orator section and the condenser section, apparatus forselectively opening and closing said port, said apparatus comprising:

a door dimensioned to cover said port;

means for mounting said door for pivotal movement about an axis betweenport opening and port closing positions; and

an open-ended leaf spring for biasing said door to the port closingposition, one end of said spring being attached to said partition on oneside of said axis and the other end of said spring being attached tosaid door on the opposite side of said axis, the line of force of saidspring extending between the ends of said spring and said springsurrounding said axis when said door is shut and said line of forceshifting toward said axis as said door pivots towards the port openingposition, whereby said bias decreases from a maximum value as said dooris moved from the port closing towards the port opening position.

2. The invention according to claim 1 wherein said axis is outside theconfines of said line of force and said spring when said door is in thedoor opening position. whereby said spring biases said door in the dooropening position when said door is in said door opening po sition.

3. A control mechanism for selectively opening and closing a doordimensioned to cover a port provided in a partition between theevaporator section and condenser section of a refrigeration unitcomprising:

means for mounting said door for pivotal movement about an axis betweenport opening and port closing positions; and

spring means for biasing said door toward a port closing position, saidspring means having one end connected to a selected portion of therefrigeration unit, fixed in position relative to said door, the otherend of said spring means being connected to said door, a first forcedeveloped by said spring means acting on said door, when said door is ina closed position, to maintain intimate contact between said door andthe portion of the partition defining said port and a second forcedeveloped by said spring means acting on said door, when said door ismoved toward a port open position, to bias said door in said openposition.

4. A control mechanism in accordance with claim 3 wherein the magnitudeof the first force is greater than the magnitude of the second forcedeveloped by said

1. In an air conditioning unit having a casing, a partition dividing theunit into an evaporator section and a condenser section, and a portextending through said partition for enabling the flow of air betweenthe evaporator section and the condenser section, apparatus forselectively opening and closing said port, said apparatus comprising: adoor dimensioned to cover said port; means for mounting said door forpivotal movement about an axis between port opening and port closingpositions; and an open-ended leaf spring for biasing said door to theport closing position, one end of said spring being attached to saidpartition on one side of said axis and the other end of said springbeing attached to said door on the opposite side of said axis, the lineof force of said spring extending between the ends of said spring andsaid spring surrounding said axis when said door is shut and said lineof force shifting toward said axis as said door pivots towards the portopening position, whereby said bias decreases from a maximum value assaid door is moved from the port closing towards the port openingposition.
 2. The invention according to claim 1 wherein said axis isoutside the confines of said line of force and said spring when saiddoor is in the door opening position, whereby said spring biases saiddoor in the door opening position when said door is in said door openingposition.
 3. A control mechanism for selectively opening and closing adOor dimensioned to cover a port provided in a partition between theevaporator section and condenser section of a refrigeration unitcomprising: means for mounting said door for pivotal movement about anaxis between port opening and port closing positions; and spring meansfor biasing said door toward a port closing position, said spring meanshaving one end connected to a selected portion of the refrigerationunit, fixed in position relative to said door, the other end of saidspring means being connected to said door, a first force developed bysaid spring means acting on said door, when said door is in a closedposition, to maintain intimate contact between said door and the portionof the partition defining said port and a second force developed by saidspring means acting on said door, when said door is moved toward a portopen position, to bias said door in said open position.
 4. A controlmechanism in accordance with claim 3 wherein the magnitude of the firstforce is greater than the magnitude of the second force developed bysaid spring means.